New Jersey Statutes Title 2A. Administration of Civil and Criminal Justice 2A § 44-189.1

In addition to any other remedy available under the “Self-Service Storage Facility Act,” P.L.1983, c. 136 (C.2A:44-187 et seq.), a reasonable late fee may be charged and collected by an owner for each month that the occupant's rental payment for a storage space is in default.

For purposes of this section, a late fee of up to $20.00 or 18 percent of the monthly rent, whichever is greater, is reasonable and shall not constitute a penalty.